The research on discharge coefficient of a non-standard Venturi meter with a swirler

Abstract

Flow measurement plays an important role in the modern engineering field. And flow rate is one of the most important parameter in this process. One traditional method of deriving flow rate is measuring the pressure difference (DP) along the pipe while the concerned fluid flowing through a DP instrument, such as Venturi meter. This DP instrument is among the most widely used flow measurement instruments, available in plumbing, energy transport pipeline, petroleum chemical industries, etc. In this research, a non-standard Venturi structure is proposed to satisfy the measurement demand of the inlet multi-phase flow with complex flow pattern. Compared to the standard Venturi meter, the angles of the divergent and the convergent of the proposed device are changed to obtain a shorter pipeline. Besides, a swirler is also placed into the convergent, which would force the flow to swirl with tangential velocity and adjust the inlet gas-liquid two phase flow to annular flow. The focus of the study is directed toward the pressure profile and the discharge coefficient Cd of the proposed structure. Computational simulation of single phase flow is carried out to measure the pressure drop along x-axis via FLUENT. According to the simulation results, the addition of swirler brings an extra pressure drop in advance. At the end of the throat, there is a sudden drop of pressure, decreasing to the lowest point, which is caused by the characteristics of the precession vortex. Then the final static pressure value is obviously lower than the initial static pressure value.